Changes:
1. Add /ego-mgr slash command with subcommands:
- get, set, list, delete, add-column, add-public-column, show
- Uses pcExec to call ego-mgr binary with proper env vars
2. Rename pcexec → pc-exec throughout codebase:
- Tool name: pcexec → pc-exec
- Function exports: pcexec → pcExec, pcexecSync → pcExecSync
- Updated all references in skills and plugin files
3. Translate all Chinese text to English:
- ego-mgr-slash.ts responses
- slash-commands.ts responses
- SKILL.md files remain in English